Emerging biological treatments for asthma

Severe asthma is a chronic airway disease characterized by many pathomechanisms known as endotypes. Biological therapies targeting severe asthma endotypes have significantly improved the treatment of this disease, thus remarkably bettering patient quality of life. This review aims to describe current biological therapies for severe asthma, highlighting emerging ones. Several studies have confirmed the beneficial effects of currently available monoclonal antibodies targeting immunoglobulin E (IgE), interleukin-5 (IL-5) or its receptor, and interleukin-4 (IL-4)/interleukin-13 (IL-13) receptors (IL-4R/IL-13R). However, patients with T2-low asthma are not eligible for the above biological therapies. New treatments are now moving toward targeting the upstream pathways of asthma pathogenesis, coordinated by innate cytokines such as alarmins. These key proinflammatory mediators orchestrate the activation of complex cellular networks including both innate and adaptive immune responses. Alarmins include thymic stromal lymphopoietin (TSLP), interleukin-25 (IL-25), and interleukin-33 (IL-33), which are released from injured airway epithelial cells. TSLP and the other alarmins are suitable targets of biological therapies which are effective for add-on treatment of type 2 asthma. Moreover, anti-alarmin monoclonal antibodies can be also beneficial for patients with T2-low, poorly controlled severe asthma.